This proposal requests support for a longitudinal study of individual differences in memory functioning in later life. The first occasion of measurement for this study was completed in 1986. The proposed research is for the second occasion of measurement in 1989. the design calls for a third occasion of measurement to be completed in 1992. The sample consists of 484 community-dwelling adults, aged 55 to 86 years at the time of the first occasion of measurement in 1986. These individuals were given a battery of tasks designed to measure memory performance, information processing and intellectual abilities, self- reported physical health, cognitive demand-level of everyday activities, beliefs and feelings about cognitive functioning, and aspects of personality. The research is rooted in earlier work which suggests that changes in memory performance may depend substantially on individual differences in the decline of ability components underlying the complex tasks typically used to measure memory. from this perspective, age-related declines in memory performance cannot be expected for all older adults, but only for those individuals who have experienced sufficient decline in the ability components necessary for successful task performance. The study is also designed to examine the potential mediators of this differential decline of abilities. First, the study will examine whether such decline may be related to physical health. Second, it will investigate whether the everyday environment of many older adults may lack demands conducive to superior cognitive functioning, thus generating cognitive atrophy through disuse. finally the study is designed to explore whether lower feelings of self-efficacy in memory-demanding situations may contribute to performance declines. In sum, the objective of the proposed research is to examine: (a) the extent to which age-related changes in memory functioning result from a pattern extent to which age-related changes in memory functioning result from a pattern of differential decline in information processing and intellectual abilities, and (b) the extent to which patterns of cognitive change in adulthood are mediated by physical health,m cognitive lifestyle, and personal belief variables.